1. Field of the Invention
The present invention relates to a stirring provision for a continuous casting plant, and in particular to a continuous steel casting plant, where at least two magnetic induction elements are operated with alternating current and are disposed successively in the longitudinal direction of the guiding of the strand, where each induction element is connected to a proper phase of the at least two phase alternating current and where the phases are shifted with respect to each other by a phase angle .PHI. from about 0 to 180 degrees.
2. Brief Description of the Background of the Invention Including Prior Art
A stirring provision of the kind set forth above has been taught in German patent application Laid Out No. DE-A 2,756,623, where a continuous relative motion of the melt is achieved in the region of the stirring provision. This results in the disadvantage that inhomogeneities are created in the cross direction of the strand (white bands) by unsteady concentration changes, which, when used, interfere with the resulting properties of the strand.
The German Patent No. DE-B 1,962,341 teaches a stirring provision, which can achieve a discontinuous metal flow in the core zone of a strand for the avoidance of segregation and liquation. Travelling inductors are taught disposed successively in the longitudinal direction of the guide of the strand, where each inductor is bar-wound. A multi-phase sinusoidal electrical voltage generates an electrical travelling field formed as a wave progressing in the longitudinal direction of the travelling field inductors. The travelling field inductors are either alternatingly switched on and off or are changed in their polarity or are supplied with a stepwise changing induction voltage in order to avoid segregation and liquation in the center of the cast strand.
This conventional stirring provision requires its own control circuit for switching on and off or for changing polarity or, respectively, for changing the induction voltage in order to achieve a discontinuous metal flow.